Censoring provocative art is the worst advert for 2012

'Unless you tell me it's withdrawn, I'm coming round to the academy and I'm going to stab the first person I see," was one of the threats received by the Royal Academy during the 1997 Sensation exhibition. The reason? Marcus Harvey's portrait of Myra Hindley, made from multiple copies of children's handprints.

Inevitably, the picture succumbed to vandalism and was removed from the show for repair, but the marks from the canvas remained on the wall, along with a plaque detailing the work. That void seemed to speak volumes about our relationship with contemporary art in this country.

Eleven years on, the picture has lost none of its power to shock - a fresh burst of outrage has followed a fleeting glimpse of the artwork in a Visit London video screened in Beijing to promote the 2012 Olympics. The picture appears in a montage of images highlighting London's thriving cultural scene.

Critics of Harvey have long argued that any portrait of Hindley was bound to cause controversy. Yet the power of this one was in the children's handprints that seemed to claw at Hindley's face, obliterating her features with their tiny grasping palms. It had the chill of horror we feel but can rarely express. In an interview at the time with the writer Gordon Burn, Harvey said: "I just thought that the handprint was one of the most dignified images that I could find. The most simple image of innocence absorbed in all that pain."

If an artist's role is to visualise emotions we find too powerful to elucidate, then Harvey's potent, if macabre, image is very cathartic indeed. Yet both Boris Johnson and the prime minister seem to have overlooked this fundamental role of art. Spokesmen for the Mayor's office and Downing Street have already condemned the use of the painting in the video and asked for its withdrawal. Perhaps they should have thought to ask the then-director of the Royal Academy, Sir Norman Rosenthal, who argued that Harvey's painting was the single most important work of the Sensation exhibition and fought so hard to include it.

London may not have 40,000 drummers or an unlimited budget with which to herald the opening ceremony in 2012, but it does have a rich cultural heritage that is energising, all-embracing and supposedly uncensored. Let us not jeopardise this at the first hurdle.